Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men – Research Review

Schoenfeld BJ et. al. “Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men.” J Strength Cond Res. 2014 Apr 7. 

Regimented resistance training has been shown to promote marked increases in skeletal muscle mass. Although muscle hypertrophy can be attained through a wide range of resistance training programs, the principle of specificity, which states that adaptations are specific to the nature of the applied stimulus, dictates that some programs will promote greater hypertrophy than others. Research is lacking, however, as to the best combination of variables required to maximize hypertophic gains. The purpose of this study was to investigate muscular adaptations to a volume-equated bodybuilding-type training program versus a powerlifting-type routine in well-trained subjects. 17 young men were randomly assigned to either an HT group that performed 3 sets of 10RM with 90 seconds rest or an ST group that performed 7 sets of 3RM with 3 minutes rest. After 8 weeks, no significant differences were noted in muscle thickness of the biceps brachii. Significant strength differences were found in favor of ST for the 1RM bench press and a trend was found for greater increases in the 1RM squat. In conclusion, this study showed both bodybuilding- and powerlifting-type training promote similar increases in muscular size, but powerlifting-type training is superior for enhancing maximal strength.

Introduction

Ok, so assuming you made it through the Categories of Weight Training series re-run/re-write, you hopefully saw that there is a general belief/schema whereby different loading parameters (intensity, volume, etc.) generate differential results in terms of muscular endurance, muscle growth, muscle strength.

This isn’t a new idea, mind you for years folks talked about the repetition continuum which basically is what I presented in too many words.  Low reps build strength (but minimal or no size), medium reps build growth (with less of an impact on strength) and high reps build endurance (with little to no impact on size of strength).

Of course there is always overlap and you probably noticed that, as I laid it out, the different repetition ranges tended to bleed into one another with the low or high-end of one range usually being the high or low-end of the next (i.e. maximal strength is 1-5 reps and 5 reps is where the hypertrophy range starts, hypertropy can range from 5-20 reps which is about where muscular endurance starts).

Of course, that’s what a continuum means.  Put differently, it’s important not to think of these repetition ranges or distinct and separate categories where moving 5 to 6 or 12 to 13 repetitions causes you to magically move from one adaptation to another.  It’s just a matter of degrees of what you will develop.  Or so the idea goes.

Now, in general, previous studies have mostly supported the repetition continuum of low reps for strength, medium reps for growth, high reps for endurance.  But many if not all of them have suffered from one crucial flaw, the total volume of training was different.  That is, say we compare a strength program of 3 sets of 3 to a hypertrophy program of 3 sets of 10 and find that 3×3 builds strength and 3X10 builds size.  Aha, concept proven.

Except that there is more than one variable being compared here, if nothing else you’re comparing 9 total reps to 30 total reps (mind you, this is sort of inherent to those types of training in the first place).   And without getting into the variously proposed mechanisms for growth, a question that such a study doesn’t answer is whether it’s simply an issue of volume that is determining the difference.  That is, if you could do 30 reps as 10 sets of 3, would you get the same growth as the 3 sets of 10?   Would you get more growth?  Would strength gains be different?

Mind you, at a fundamental level, that’s part of the point: something I mentioned a fair few times in my article series is that, practically you tend to be limited in how many total sets you can do with certain loading schemes (i.e. 10 sets of 3 on a decent rest interval takes forever compared to 3 sets of 10 even if both give you 30 reps).  But I’m getting ahead of myself.

 

The Paper

Enter the paper I want to talk about today, done by Brad Schoenfeld and his colleagues.  Brad has been doing some interesting work of late and it’s clear that his background in actual weight room practices is informing his study designs since they are showing at least some relationship to what actual trainees actually  do.  And this is a good example of that.   On to the paper.

20 males were recruited and statistical wanking determined that this would be a sufficiently powered study (in terms of being able to determine real differences).  All subjects had lifted weights at least 3 times per week for at least a year (and were defined as experienced) and the average training experience was 4.2±2.4 years with a range of 1.5 to 10 years of training.  We might quibble if someone with 1.5 years in the weight room is truly experienced but the point is that they weren’t beginners (for whom anything and everything generates about the same response).

They were divided into one of two groups, strength training or hypertrophy training and three subjects failed to complete the study, 2 because of injury and one for personal reasons.  8 subjects completed the strength training protocol and 9 the hypertrophy protocols.

The individual training protocols were set up in an attempt to mimic a typical training program that might be used by a bodybuilder or powerlifter with a mix of lower body and upper body (both pushing and pulling movements).  Both groups used identical exercises which is a big strength of the study (even if it doesn’t necessarily represent actual training practices), just distributed differently throughout the week and with different loading.  I’ve replicated the training programs below.

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Protocol Wkout 1 Wkout 2 Wkout 3
Strength

Incline BB press, Machine leg press, Wide grip pulldown

Flat BB press, Barbell back squat, Close grip pulldown Hammer chest press, Leg extension, Seated cable row
Hypertrophy  Incline BB press,Flat BB press, Hammer chest press  Wide grip pulldown, Close grip pulldown, Seated cable row Barbell back squat, Machine leg press, Leg extension

 

 

So basically it was comparing a typical bodybuilder type split with a chest, leg and back day to a strength oriented routine which was full body at each workout (with a leg, push and pull movement).  The loading parameters were 7 sets of 3 with a 3 minutes rest for the strength protocol and 3 sets of 10 with a 90 seconds rest for the hypertrophy protocol; each group took each set to failure and all workouts were supervised by an NSCA certified trainer.   I should mention that load equalization had to do with tonnage (sets * reps * load lifted) and not just reps (the strength group did 63 reps per week on each muscle, 21 per workout and the hypertrophy group did 90 reps).

Both groups were tested (for 10RM and 3RM respectively) to set initial training loads.   As well, 1RM in back squat and bench press were tested at the start and end of the study.  To measure muscle growth, only one muscle, the biceps was measured and this was done by Ultrasound measurement to determine thickness at the beginning and end of the study.

Diet was uncontrolled and this is arguably the weakest part of the study (although this is just a realistic concession to cost; controlling diet over 8 weeks is insanely expensive); dietary recalls were used and subjects received a 24 gram protein supplement on training days.

In terms of the results, I’ve reproduced the changes in biceps size below.

Strength Hypertrophy
Beginning End Beginning End
35.3±5.7 39.6±5.1 34.5±4.2 38.7±4.3

Which represented an increase in biceps size of 12.6% and 12.7% for the hypertrophy and strength groups respectively and there was no difference between the two groups.

In terms of maximal strength increases, the results are as follows (I think values are in kilograms but can’t find it in the study for some reason):

Strength Hypertrophy
Beginning End Beginning End
Bench 104.8±26.6 115.9±21.5 97.1±20.6 105.1±18
Squat 109.6±597 147.7±40.9 114.5±36.5 136.1±30.6

Which represented an increase of 9.1% vs. 13% in the bench and 22.2% vs. 25.9% in the squat  for the hypertrophy versus strength groups respectively (i.e. the strength group made better strength gains).

Basically, both groups made similar gains in biceps size and the strength group did better in terms of increasing squat and bench 1RM.

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My Comments

So that’s the study.  And by and large, with a few minor nitpicks (that are always present) it was laid out fairly reasonably.  Keeping the exercises identical across groups is a huge strength of the study since it helped to limit the number of variables being compared.  Certainly in practice powerlifters and bodybuilders might select different exercises; and most bodybuilders would do direct arm work but at that point you’ve got too many variables to draw any conclusions.

And while we might quibble about the split used (especially given data suggesting that growth is optimal with a twice per week training frequency) the simple fact is that the training program used is representative of much bodybuilding training with each muscle group getting hammered once per week.  Right or wrong, this study did more or less mimick what the different types of athletes have done.  And clearly didn’t limit growth in the single measured muscle group.

Tangentially, this is probably the biggest headscratcher of all; given that the measurement method used was surface Ultrasound (which is non-invasive) and can’t have been difficult or taken much time, I have no idea why at least the quads weren’t measured as well to see if the same growth response occurred.

Edit: In the comments below Brad explained that they did attempt to measure quad thickness but didn’t get enough good data for it to be a statistically meaningful piece of data (so it wasn’t reported) but that the trend was for increased muscle size to be identical between groups.

So what about that growth result?  As I detailed above, the study found that, when volume load was equated, the growth in the biceps was identical across groups (I’m sure some pundit has also noticed the fact that there was arm growth despite there being no direct arm work, only compound pulling) which certainly raises the question of distinct hypertrophy and strength training methods.  Anyone who slogged through the Categories of Weight Training series that led into this might note that I mentioned that some argue that growth will the same with low rep training so long as you do enough sets and this seems to support this idea.  I’ll come back to this in a second.

Mind you, there was clearly a difference in 1RM strength gains with the strength group showing a superior gain in 1RM.  Mind you, the hypertrophy group still improved their 1RM, pointing again to the fact that you never get just a single adaptation to any type of training (another point made in my series).  Clearly low reps can cause growth and higher reps can improve even maximal strength.  It’s often just a matter of degrees.

So case, closed, right?  Just do a ton of volume with low reps and you can get both growth and strength .  No need to muck around with high reps (or reverse your interpretation: why much around with all of that nasty low rep training when high reps build as much size and almost as much strength without all of the heavy lifting).  Right?  Well, no.

Because there’s actually a bit more lurking underneath this paper that most (who probably stopped and started at the abstract or title) missed and that needs to be considered.  Points that the researchers themselves made in the body of the paper regarding the results.  I’ll just quote them:

“It is important to note that there were substantial differences in the duration of training between the 2 protocols studied.  The [hypetrophy] protocol took approximately ~17 minutes to perform, while the [strength] required a time commitment of more than 1 hour.  Given the similar hypertrophic gains between groups, [the hypertrophy protocol] was a much more time-efficient strategy for eliciting these increases. Moreover, personal communications with subjects both during and after the study revealed that those in the [strength] group generally felt highly fatigued both physically and mentally from the workouts while the [hypetrophy] group tended to report being willing and able to extend the duration of their training.  It therefore stands to reason that the [hypertrophy] group could have endured additional volume in their routines while those in the [strength] group were at their upper limits of tolerance.”

And those are both really important points. I made the first one explicitly when I talked about the time requirements of maximal strength training.  Even if it is possible to get the same volume with low rep training, it simply takes forever to get the work in.  So 10 sets of 3 on a 3′ break takes a minimum of 30 minutes for one exercise (more with warmups), 3 sets of 10 with a 1′ break takes maybe 6 minutes.  That’s compounded with the second point, the hypertrophy group could have easily done more volume since the time/effort requirement was so much lower.    By the time you double your tonnage/total reps in higher repetition ranges, you’re simply at a point that can’t be realistically achieved with low-rep training.

A final point is the injury issue with low repetition training. Again quoting the researchers

“A common area of concern with powerlifting-type training is an increased potential for injury.  The performance of high training volumes using very heavy loads places substantial stress on the joints and soft tissue structures…Although a small sample, the present study gives credence to the veracity of these concerns.  Two of the 10 subjects in the [strength] groop dropped out of the study due to joint-related injuries…The injuries occurred despite direct supervision by trained personell.  In contrast, none of those in the [hypertrophy] group reported experiencing a training-related injury”

So not only was the hypertrophy training more time efficient, it would also appear to be safer.  Which is not to be read that I’m saying that the hypertrophy program was necessarily superior.    I’m just reporting/re-iterating what the study found.

Finally it’s worth noting that the study was only 8 weeks long and no mid-point measurements were made to avoid interrupting the study (often you see different rates of growth or strength with different protocols).  Also keep in mind that ONLY the biceps was measured and there’s no guarantee that the results are generalizable to other muscle groups.  Those and a few other limitations were discussed explicitly by the researchers which is always a good sign (researchers discussing the limitations of the study that often science reporters overlook).

Now a lot of people have used this paper (depending on their own bias) as proof that one style of training is inherently better than the other.  Folks enamored with low rep training are using it to claim that “Low reps are just as good for growth as high reps and you get stronger.” and folks enamored with high rep training are using it to claim the opposite.  Some have criticized it for seeming to suggest that “Volume Doesn’t Matter” or “High Repetition Training is Superior” thinking it loaded to find one result or another.

But it’s important to note that the point of this study was not actually an attempt to determine whether heavy strength training or hypertrophy training was superior for generating growth or strength (a point Brad made himself in a discussion on Facebook about the paper a few weeks back).  Rather, the study simply set out to mechanistically examine the issue of whether growth (or strength gains) would be different or the same when loading volume was equated.  That’s it, it was just a mechanistic thing because that’s what a lot of science is.

However, the researchers do offer:

“Based on the findings, strength-related gains appear to be maximized by performing heavy- as compared to moderate- load training, although both protocols significantly and markedly improved indices of maximal strength. On the other hand, increases in muscle thickness in experienced lifters appear to be similar in bodybuilding- and powerlifting-type when volume-load is controlled, at least over a relatively short time period.

The greater time efficiency of bodybuilding-type training would seem to make it a superior choice for those seeking to increase muscle mass, although these results are limited to the biceps brachii and cannot necessarily be generalized to other muscles.

And it’s hard to say much more than that.  Clearly the hypertrophy routine gave identical growth in 1/3rd as much time although the absolute strength gains were lower (though 1RM still went up).  Given the limited relevance of the 1RM to the average trainee, I’m not sure this is a point worth quibbling about.  I know everyone on the Internet has a raging hard-on for 5X5 and heavy training but if 3 sets 10 gives you the same growth response, almost the same strength gains and does it in 1/3rd as much time with less risk of injury, the proper conclusion is probably that the hypertrophy training protocol was superior.

They finish stating:

“Whether combinations of different loading schemes would produce a synergistic response that enhances muscular adaptations remains to be determined and requires further study.”

The last point is really a key one, of course; while it’s always fun to debate this stuff back and forth, in the real world it’s fairly rare to find anyone using a single repetition range in the gym.  Powerlifters have long supplemented their heavy strength work with higher repetition “hypertrophy” work (and Chinese Olympic lifters are doing the same in recent years).  Even the most hardcore 5X5 advocates usually allow for some higher rep work after the main movements (this goes back to Bill Starr who programmed 5X5 and allowed up to 40 reps of “Beach work” for showy muscles afterwards).    It is probably more common for bodybuilders to stick exclusively to higher repetition ranges, mind you.  But even there there is often a mixture.

But addressing whether that is better, worse or no different will wait for another study.

Let the bickering begin!

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